scribner



(NoModel.) 4

C. E. SCRIBNER.

1 TELEPHONE CIRCUIT. 110.584,41?. Patented June 15, 1897.

712%@ @y ffm CIIARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TOTIIE XVESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE-CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 584,417, dated June 15,1897..

Application filed November 4, 1895. Serial No. 567,839. (No model.)

To @ZZ whom, it may concern,.- The station equipment to which thepresent Beitknown that I, CHARLES E. SCRIBNER, a application relates isintended' particularly citizen of the United States, residing at Chiforuse in association witha system of signals cago, in the county of Cookand State of Illi- Which requires the presence ofa considerable 5 nois,have invented a certain new and useful current in the telephone-lineduring its use 55 Improvement in Telephone- Circuits, (Case forconversation.

No. 407,) of which the following is afull, clear, The invention consistsin so arranging the concise, and exact description, referencebedifferent appliances at the station that the ing had to theaccompanying drawing, formlocal storage battery may be in position to 1oing a part of this specification. receive the required charging-currentduring 6o My invention concerns the arrangement of the idleness of theline and to discharge apparatus at telephone-substations atwhich throughthe local circuit of the transmittingthe transmitting-telephones aresupplied with telephone during the use of this instrumentexciting-current from storage batteries at the as long as the battery isproperly charged,

I5 stations, the batteries being charged by curbut that it may act as apolarization-cell to 65 rents constantly iiowing inthe lines from adivert current from the line through the same central source while thetelephones are not local-transmitter circuit when nearly or quite inuse. discharged. This contrivance greatly dimin- It consists in a newarrangement of the cirishes the danger of interruption of the servzocuit connections of the station appliances deice from failure of theexcitingcurrent. 7o signed to permit a different mode of operat- Whilethe local storage battery is charged ing the telephones in the event ofthe comthe normal efficiency of transmission will be plete discharge ofthe local storage battery obtained; but in case of complete discharge toavoid interruption of service, and serving of the local battery from anyof several causes 2 5 incidentally to simplify the circuits. which mayoperate transmission may still be 7 5 Vhen a storage battery is nearlyor quite satisfactorily effected, although with somedischarged or, if itbe of the Plante type, is what less e'fiiciency than before. The newarunformed, its electromotive force will be inrangement oi' circuits hasalso some other adsufticient for properly excitin gatransmittingvantages, chief among which is its simplicity.

3o telephone; but if current be sent through the The invention is shownin the'accoinpany- 8o battery in the direction to charge it a considingdrawing. k erable counter electromotive force is instantly Thetelephonie appliances at the substation developed nearly equal to thatof the charged comprise a transmitting-telephone a, a recell. W'hen acurrent is permitted to fiowin ceiving-telephone b, an induction-coil c,and

3 5 the-telephone-line during the use of the line, a storage battery CZof two cells. In addition 85 this action of the discharged storage-cellmay to these a signal-bell e of high resistance is be utilized to divertcurrent through the placed at the station, and a telephone-switchtransmitting instrument for its operation, the f, which controls thecontinuity of the teleeiciencyof transmission under suchcircumphone-circuits. This switch f is provided 4o stances beingfavorably comparable with that with two contact-points f and f2, withwhich 9o experienced when the charged cell is used. it makes contactwhen the lever f3 of the This action of the uncharged battery in theswitch is permitted to rise. circuit and its use in operating atelephone- The storage battery CZ and the high-resisttransmitter havebeen described in and made ance bell e are included serially in a bridge45 the subject of a prior application, Serial No. or cross connection lof the line-circuit 2 95 547,624, iiled April 30, 1895,(Case No. 385.)In The receiving-telephone and the secondary that application I havedenominated the cells helix c2 of the induction-coil c are placed in souse( polarization-cells and will hereina branch from line conductor 2,terminating after employ the same term in this speciiicain thecontact-anvil f of the switch. The

5o tion. transmitting -telephone ct and the primary loo Winding c ofcoil c are in a branch 5 from line conductor 2, terminating in the leverf3 of the switch. A Wire G is led from bridge l'intermediate of thebattery and bell to the contact-anvilf2 of the switch.

lt will be observed that there are thus a permanently-closed bridge l ofthe line-circuit containing the bell and the battery, a normally openbridge of the circuit controlled by the switch, including` Wire 4, asecondary heliX of the induction-coil, the receiving-telephone,switch-contactsff2, wire 6, and a portion of Wire l, and a normally openlocal circuit about battery d, made up of a portion of Wire l, Wire 5,including the transmittingtelephone and the primary helix of theinduction-coil, switch-lever f 3, contact f2, and wire 6. Vhen thereceiving-telephone is removed .from its support, the switch closes thebranch containing the receiving-telephone and completes also the localcircuit about battery d,

The line conductors maybe led at the exchange through impedance-coils gand 72, to the poles of a central charging-battery t'. A spring-jack 7cis shown connected with the line and a lamp-signal Z is included in lineconductor 2 and placed near the spring-jack. The battery t' creates inthe line a current which circulates, while the line is not in use,through the local storage battery dand the bell e at the substation. Thelocal battery is thus continuously receiving a charging-current, whichmay in practice amount to twohundredths of an ampere. v

Vhen the receiving-telephone t at the substation is brought into use, alow-resistance path is formed through this instrument, wherebysufficient current is permitted to ilow in the line to-illuininate thelamp Z and give the signal. VThe local circuit of battery d is nowclosed through the transmitting telephone and the induction-coil, sothat conversation may be carried on by means of the transmitter.

If the storage battery d be fully charged, it will supply a current ofmaximum voltage and volume to the transmitting-telephone and permit thetransmission of telephonie currents with the highest efliciency. lf,however, the battery be nearly or quite discharged from excessive use orfrom any other cause, the current which tends to iiow from the centralcharging-battery 1I through the line-circuit and through battery CZ,Wire G, and receivingtelephone Z9 will eXcitea considerable counterelectromotive force in the battery, by Which a large portion of thecurrent Willbe diverted through the transmitting-telephone a and theprimary winding of the induction-coil. Conversation will thus still bepossible as long as current is maintained in the line-circuitfrom thecentral battery.

I claim as my invention- The combination with a telephone-line, of acentral supply-battery in connection therewith, a bell and a storagebattery permanently connected serially in the line at the substationthereof, an induction-coil, a receivingtelephone in circuit with thesecondary Winding thereof, a transmitting-telephone in circuit With theprimary Winding thereof, a switch, and circuit connections controlled bythe switch adapted to bring the receiving-telephone and secondaryWinding of the induction-coil into shunt of the bell, and thetransmitting-telephone and the primary winding of the induction-coilinto shunt of the battery, as described.

In Witness whereof I hereunto subscribe my name this 17th day ofSeptember, A. D. 1895.

CHARLES E. SCRIBNER. Witnesses:

ELLA EDLER, LUcILE RUSSELL.

